Tesla Motors

Comment: Tesla CEO Elon Musk recently announced that the company would make its patents avail abe for free use, saying the company’s competitors are not other electric carmakers but any company making a car that runs on gasoline.

data from FinViz

Air Methods

Comment: Air Methods provides air medical transportation services throughout the U.S. Late last month, the company acquired the four air bases of Baptist LifeFlight, which provides services to Florida’s panhandle as well as southern Alabama and Mississippi.

Herbalife

Comment: In March, the company announced it received a Civil Investigated Demand from the FTC. Bill Ackman and Carl Icahn are famously on opposites sides of bets on the company: Ackman thinks the stock will go to zero, Icahn owns 25% of the company.

data from FinViz

Theravance

Theravance

Ticker: THRX

Short interest: 27.9%

YTD return: -15%

Sector: Biopharmaceuticals

Comment: Theravance and its partner GlaxoSmithKline announced on July 1 that they are seeking expanded use for their respiratory drug, Breo Ellipta, from the U.S. FDA.

data from FinViz

U.S. Steel

Wikimedia Commons

Ticker: X

Short interest: 28%

YTD return: -11.8%

Sector: Basic Materials

Comment: On June 27, S&P announced that U.S. Steel would be removed from the S&P 500 in favor of Martin Marietta Materials. U.S. Steel joined the S&P MidCap 400 after the close on July 1.

data from FinViz

Invensense

Invensense

Ticker: INVN

Short interest: 28.5%

YTD return: 10%

Sector: Technology

Comment: Invensense makes decies for interfaces that track an object’s movement, and in its fiscal year ended March 30, Invensense reported revenue of $252 million, up from $209 million the prior year.

data from FinViz

SolarCity

Comment: In June, SolarCity announced plans to build one of the world’s largest solar plants in upstate New York. The company’s chairman is Elon Musk, the CEO of Tesla, another company that appears on this list.

BlackBerry

Comment: BlackBerry shares have been on a tear since the handset maker reported earnings last month that showed it turned a $0.04 per share profit in the first quarter.

data from FinViz

Questcor

Mallinckrodt

Ticker: QCOR

Short interest: 32.2%

YTD return: 70%

Sector: Pharmaceuticals

Comment: In April, Questcor and Mallinckrodt announced an agreement to merge in a deal expected to close during the third quarter. The New York Times noted, however, there are pretty big risks associated with Questcor’s Achtar immune-system drug.

Autohome

Comment: Autohome, which sells cars online in China, announced an agreement with Baidu last month to enhance search results for computers running Baidu’s Aladdin platform.

data from FinViz

Lululemon

Honest Slogans

Ticker: LULU

Short interest: 36.9%

YTD return: -30%

Sector: Athletic Apparel

Comment: The company’s founder Chip Wilson, who stepped down as chairman of the board in December, is working with Goldman Sachs to get control of the company back. Wilson is Lululemon’s largest shareholder.

data from FinViz

Amtrust Financial Systems

Amtrust Financial

Ticker: AFSI

Short interest: 38.7%

YTD return: 30%

Sector: Insurance

Comment: Amtrust Financial has increased gross written insurance premiums 36% each year over the last five, but some have begun to wonder if the company can sustain its growth.

data from FinViz

Zulily

Business Insider / Jillian D’Onfro

Ticker: ZU

Short interest: 41%

YTD return: -6%

Sector: Online Retail

Comment: Zulily is a daily deals site for moms, and we recently toured their Seattle offices. In May, the company reported sales that grew 87% in the first quarter and raised its fiscal-year revenue expectations.